.back-to-top {
  position: fixed;
  right: max(16px, env(safe-area-inset-right));
  bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 1000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 8px 13px;
  color: #ffffff;
  background: #1b5f78;
  border: 1px solid #154c61;
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(20, 45, 65, 0.22);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 160ms ease, transform 160ms ease, visibility 160ms ease;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top:hover,
.back-to-top:focus-visible {
  color: #ffffff;
  background: #124d63;
}

@media (prefers-reduced-motion: reduce) {
  .back-to-top {
    transition: none;
  }
}

@media (max-width: 640px) {
  .back-to-top {
    right: max(10px, env(safe-area-inset-right));
    bottom: max(10px, env(safe-area-inset-bottom));
    min-height: 40px;
    padding: 7px 10px;
    font-size: 13px;
  }
}